Abstract
Spectral tailoring of an amplitude-modulated radio-frequency (RF) pulse may be used to modify the slice-profile produced by a selective excitation sequence. Optimisation of the profile by intuitive means is difficult, however, due to the non-linearity of the magnetisation's response. A design procedure is presented which uses computer-simulation to calculate the response to an arbitrary RF envelope, and alters systematically the shape of the envelope in order to optimise the slice-profile. Two forms of modulation function are suggested, both based on a truncated-sinc, and the simulated response to optimised 90° and 180° pulses is shown. The effect on the slice-profile of RF magnetic field inhomogeneity is discussed.
Original language | English |
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Pages (from-to) | 235-243 |
Number of pages | 9 |
Journal | Magnetic Resonance Imaging |
Volume | 3 |
Issue number | 3 |
DOIs | |
Publication status | Published - 1 Jan 1985 |
Keywords
- NMR Imaging
- Numerical optimisation
- Selective excitation